铜对隆线溞趋光行为的抑制作用及其致死效应

Evaluating the Biotoxicity effect of Copper by the Phototactic Behaviour of Daphnia carinata and LC_(50)

采用隆线潘（Daphnia carinata）纯生物株Dc42为试验生物，参照ISO6341大型潘活动抑制试验及ISO6241大型潘致死生物试验法，研究水体中Cu^2＋对隆线潘3h趋光行为的抑制作用及其24—96h的致死效应。结果表明，隆线潘的趋光指数（Ip）与Cu^2＋浓度存在着明显的负相关关系（R^2=0．994，P〈0．001），随着溶液中Cu^2＋浓度的增加，趋光指数急剧下降。Cu^2＋导致隆线潘趋光性发生显著改变的检测下限远低于LC50。其3h-Ip监测下限（0．0056mg／L）比24h—LC50（0．031mg／L）及48h—LC50（0．021mg／L）分别低81．94％和73．33％；仅相当于96h—LC50（0．006mg／L）。铜对不同时段隆线潘死亡率影响与3h趋光指数下降的趋势相似，在0．0032mg／L至0．1mg／L的浓度范围内，隆线潘各时段死亡率与浓度之间并不呈直线关系，而是呈Boltzmann曲线关系，相关系数均为0．995以上。因此，趋光指数是一个较为灵敏的毒理学指标，利用隆线潘趋光行为抑制法来判断Cu^2＋生物毒性的大小，具有快速、简便等优点，并能在短时间内获取具有高度重复性的实验数据。研究结果可为建立利用隆线潘趋光行为抑制法评价化学物质生物毒性提供快速的测试方法，为进一步了解重金属污染的生态毒性效应提供理论依据。

The study on the biotoxicity of varying copper concentrations by the phototactic behaviour of Daphnia carinata and LC50. The results showed that heavy metal biotoxicity was correlated with themselves but also with the their levels in waters. Resulting that none of linear relationships was founded between biotoxicities and concentrations of heavy metals in solutions. It seems reasonable to suggest that. Referred ISO6341 bioassay methods, the subject used a specific Daphnia carinata clone （Dc 42） in the present experiment to study the effects of chromium on phototactic behavior. The results show that the of D. carinata decreases with the rise of Cr^6＋ concentration （R2 = 0. 994, P 〈 0. 001 ）. Being compared with the standard LC50 bioassay, the lower limit detection concentration （LLDC = 0. 005 6 mg/L） of 3 h -Ip was 81.94% and 73.33% lower than 24 h - LC50 （0. 031 mg/L） and 48 h - LC50 （0. 021 mg/L） ,respectively;just as 96 h - LC50 （0. 006 mg/L）. Therefore,the phototactic index （Ip） inhibition is a more sensitive toxicology index than LC50, and the new biotechnology can greatly shorten the test time that the speed of test is 8-16 times higher than the standard LC50. The method for bio-evaluating acute toxicity of chemicals and detecting pollutants in water are efficient, sensitive, economical and quick.